function [ ] = mx_eyelink_get_sample( )
%MX_EYELINK_GET_SAMPLE Gets an integer (unconverted) sample from end of queue,
% discards any events encountered.
%
% Returns:
% 0 if no data. 1 if data retrieved.
% sample 	Pointer to buffer (ISAMPLE or ALL_DATA type).
%
%
%    UINT32      time;           /*!< time of sample */
%    INT16       type;           /*!< always SAMPLE_TYPE */
%    UINT16      flags;          /*!< flags to indicate contents */
%    INT16       px[2];                  /*!< pupil x */
%    INT16       py[2];                  /*!< pupil y */
%    INT16       hx[2];                  /*!< headref x */
%    INT16       hy[2];                  /*!< headref y */
%    UINT16      pa[2];          /*!< pupil size or area */
%    INT16       gx[2];                  /*!< screen gaze x */
%    INT16       gy[2];                  /*!< screen gaze y */
%    INT16       rx;                             /*!< screen pixels per degree */
%    INT16       ry;             /*!< screen pixels per degree */
%    UINT16      status;         /*!< tracker status flags    */
%    UINT16      input;          /*!< extra (input word)      */
%    UINT16      buttons;        /*!< button state & changes  */
%    INT16       htype;          /*!< head-tracker data type (0=none) */
%    INT16  hdata[8];        /*!< head-tracker data */
%
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% Copyright Eduardo Aponte 2013
% aponteeduardo@gmail.com